Implantable medical device with anti-infection agent

ABSTRACT

An implantable medical device with anti-infection agent. The implantable medical device may be configured for placement in the head of a patient and for monitoring or treatment of the brain. The implantable medical device may have a housing or it may have a housing and a member for providing a smooth interface between the device and the adjacent tissue. The anti-infection agent may be provided on or impregnated in the housing or the member. In some embodiments, the device includes a single module while in other embodiments a plurality of modules are coupled to provide a smaller profile. In some embodiments the implantable medical device may include both anti-infection and lubricious materials.

RELATED APPLICATIONS

This application is a continuation-in-part of:

-   1. U.S. patent application Ser. No. 10/730,873, filed on Dec. 9,    2003, now U.S. Pat. No. 7,242,982, issued on Jul. 20, 2007, and    entitled “OVERMOLD FOR A MODULAR IMPLANTABLE MEDICAL DEVICE” to    Singhal et al., which in turn claims the benefit of:    -   a. U.S. Provisional Application Ser. No. 60/431,854, filed on        Dec. 9,2002, entitled “CRANIAL NEUROSTIMULATOR AND METHOD,” to        Skime et al.;    -   b. U.S. Provisional Application Ser. No. 60/471,262, filed on        May 16, 2003, entitled “IMPLANTABLE CRANIAL MEDICAL DEVICES AND        METHODS,” to Wahlstrand et al.;    -   c. U.S. Provisional Application Ser. No. 60/503,945, filed on        Sep. 20, 2003, entitled “IMPLANTABLE CRANIAL MEDICAL DEVICES AND        METHODS,” to Wahlstrand et al.;    -   d. U.S. Provisional Application Ser. No. 60/503,946, filed on        Sep. 20, 2003, entitled “IMPLANTABLE CRANIAL MEDICAL DEVICES AND        METHODS,” to Wahlstrand et al.; and    -   e. U.S. Provisional Application Ser. No. 60/507,857, filed on        Oct. 1, 2003, entitled “THIN NEURO STIMULATION SYSTEM, DEVICE        AND METHOD,” to Wahlstrand et al.

The following co-pending and commonly-assigned U.S. patent applicationsfiled on even date herewith, are also incorporated herein by reference:

-   1. U.S. patent application Ser. No. 10/731,869, filed on Dec. 9,    2003, entitled “MODULAR IMPLANTABLE MEDICAL DEVICE,” to Wahlstrand    et al.;-   2. U.S. patent application Ser. No. 10/731,868, filed on Dec. 9,    2003, entitled “IMPLANTATION OF LOW-PROFILE IMPLANTABLE MEDICAL    DEVICE,” to Singhal et al.;-   3. U.S. patent application Ser. No. 10/731,881, filed on Dec. 9,    2003, which issued as U.S. Pat. No. 7,392,089 on Jun. 24, 2008, and    is entitled “REDUCING RELATIVE INTERMODULE MOTION IN A MODULAR    IMPLANTABLE MEDICAL DEVICE,” to Wahlstrand et al.;-   4. U.S. patent application Ser. No. 10/731,699, filed on Dec. 9,    2003, entitled “COUPLING MODULE OF A MODULAR IMPLANTABLE MEDICAL    DEVICE,” to Janzig et al.;-   5. U.S. patent application Ser. No. 10/730,877, filed on Dec. 9,    2003, entitled “LOW-PROFILE IMPLANTABLE MEDICAL DEVICE,” to Singhal    et al.;-   6. U.S. patent application Ser. No. 10/731,867, filed on Dec. 9,    2003, which issued as U.S. Pat. No. 7,529,586 on May 5, 2009, and is    entitled “CONCAVITY OF AN IMPLANTABLE MEDICAL DEVICE,” to Wahlstrand    et al.;-   7. U.S. patent application Ser. No. 10/730,878, filed on Dec. 9,    2003, entitled “LEAD CONNECTION MODULE OF A MODULAR IMPLANTABLE    MEDICAL DEVICE,” to Singhal et al.;-   8. U.S. patent application Ser. No. 10/731,638, filed on Dec. 9,    2003, which issued as U.S. Pat. No. 7,212,864 on May 1, 2007, and is    entitled “MODULAR IMPLANTABLE MEDICAL DEVICE,” to Wahlstrand et al.;-   9. U.S. patent application Ser. No. 10/835,233, filed Apr. 29, 2004,    which issued as U.S. Pat. No. 7,263,401 on Aug. 28, 2007, and is    entitled “IMPLANTABLE MEDICAL DEVICE WITH A NONHERMETIC BATTERY,” to    Wahlstrand et al.;-   10. U.S. patent application Ser. No. 10/835,232, entitled    “EXPLANTATION OF IMPLANTABLE MEDICAL DEVICE”, to Wahlstrand et al.,    filed Apr. 29, 2004 now abandoned;-   11. U.S. patent application Ser. No. 10/835,527, entitled    “IMPLANTATION OF IMPLANTABLE MEDICAL DEVICES” to Wahlstrand et al.,    filed Apr. 29, 2004;-   12. U.S. patent application Ser. No. 10/835,548, filed on Dec. 9,    2003,” which issued as U.S. Pat. No. 7,317,947 on Jan. 8, 2008, and    is entitled “HEADSET RECHARGER FOR CRANIALLY IMPLANTABLE MEDICAL    DEVICE” to Wahlstrand et al., filed Apr. 29, 2004; and-   13. U.S. patent application Ser. No. 10/835,245, entitled “BATTERY    HOUSING CONFIGURATION” to Wahlstrand et al., filed Apr. 29, 2004.

TECHNICAL FIELD

The invention relates to medical devices, and more particularly, toimplantable medical devices that deliver therapy to and/or monitor apatient.

BACKGROUND

Implantable medical devices (IMD's) carry the risk of causing infectionin the patient. Bacteria on the surface of the IMD can result in seriouspatient problems.

It is desirable to implant IMD's near the site of treatment (e.g., inthe head when the IMD is a brain stimulator). These remote locationsoften provide spaces that are either small or shaped in such a way thattraditional IMD's do not fit therein or for which it is desirable tocreate a smooth interface with the surrounding tissue. Differentconfigurations of IMD's may be devised to better fit into these spaces.However, these different configurations raise questions about thepossibility of increased infection.

SUMMARY

In general, the invention relates to an implantable medical deviceincluding an anti-infection agent on the external surface or impregnatedin the external surface for reducing the likelihood of infection.

Various embodiments of the invention are presented including a devicefor implantation in the head of a patient. Some more specificembodiments configure the device for implantation between the craniumand the scalp.

Various embodiments also include a member coupled to the module ormodules for providing a smooth interface between the device and adjacenttissue. An anti-infection agent is on or impregnated in the member.

Various other embodiments also include a member coupled to the module ormodules for providing a smooth interface between the device and thescalp or the tissue near the scalp. These embodiments include ananti-infection agent on or impregnated in the member. The member may beany material capable of providing a smooth interface with the tissue.The member can include elastomeric materials, such as silicone, and/ornon-elastomeric materials such as polysulfone and polyurethane.

Various embodiments of the invention include a single module while otherembodiments include a plurality of interconnected modules. Theseembodiments include an anti-infection agent on or impregnated in thehousing or member.

Other embodiments include an implantable medical device including alubricious material and an anti-infection agent.

Methods of fabricating an implantable medical device including ananti-infection agent are also presented.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other embodimentsof the invention will be apparent from the description and drawings, andfrom the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a conceptual diagram illustrating one embodiment of animplantable medical device of the present invention.

FIG. 1B is a conceptual diagram illustrating another embodiment of animplantable medical device of the present invention.

FIGS. 1C and 1D are conceptual diagrams illustrating a modularimplantable medical device implanted in a patient according to anexample embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a modular implantable medicaldevice according to another embodiment of the present invention.

FIGS. 3A-3F are schematic diagrams illustrating various arrangements ofmodules within a modular implantable medical device according to variousembodiments of the present invention.

FIGS. 4A-4C are schematic diagrams illustrating the construction of amember of a modular implantable medical device according to the presentinvention.

FIGS. 5A-5B are schematic diagrams illustrating the interaction ofcomponents of a member according to the present invention.

FIG. 6 is a schematic diagram illustrating the degrees of motion presentin a modular implantable medical device.

FIG. 7 is a schematic diagram illustrating motion reduction withinvarious degrees of motion within a modular implantable medical device.

FIG. 8A-C are schematic diagrams illustrating example embodiments ofmodular implantable medical devices having lead management features.

FIG. 9 is a schematic diagram illustrating an example embodiment of amodular implantable medical device having an access loop for removal.

FIG. 10 is a schematic diagram illustrating a perspective view of anexample embodiment of a modular implantable medical device having atriangular module arrangement.

FIG. 11 is a schematic diagram illustrating a perspective view of anexample embodiment of a modular implantable medical device having aninline module arrangement.

FIG. 12 is a schematic diagram illustrating side view of a modularimplantable medical device having an inline module arrangement.

FIG. 13 is a schematic diagram illustrating an exploded view of amodular implantable medical device having a triangular modulearrangement.

FIG. 14 is a flowchart illustrating a method of constructing animplantable medical device with a member according to the presentinvention.

FIG. 15 is a flowchart illustrating a method of fabricating animplantable medical device including a lubricious material on orimpregnated in the housing according to one embodiment of the presentinvention.

FIG. 16 is a flowchart illustrating a method of fabricating animplantable medical device including a lubricious material on a memberaccording to one embodiment of the present invention.

FIG. 17 is a flowchart illustrating a method of fabricating animplantable medical device including an anti-infection agent on orimpregnated in the housing according to one embodiment of the presentinvention.

FIG. 18 is a flowchart illustrating a method of fabricating animplantable medical device including an anti-infection agent on orimpregnated in a member according to one embodiment of the presentinvention.

FIGS. 19A-19B are schematic diagrams illustrating another embodiment ofan implantable medical device that according to the present invention.

DETAILED DESCRIPTION

FIG. 1A is a conceptual diagram of an implantable medical device 80including housing 82 and therapy delivery element 84 (e.g., lead,catheter, extension and lead). An anti-infection agent and/or lubriciousmaterial as described herein, may be disposed on or impregnated in atleast a portion of the implantable medical device 80. In one embodimentthe anti-infection agent and/or lubricious material may be placed on thehousing 82 in the form of a coating 86. Disposing an anti-infectionagent and/or lubricious material on or impregnated in the device 80 mayfacilitate insertion of the device 80 into the implantable locationwithin a human body. The anti-infection agent reduces the likelihood ofinfection. The lubricious material reduces friction between the device80 and the tissue near the device 80. In cases where the implantablemedical device is implanted in a tight space such as between the craniumand the scalp, the lubricious material may reduce the likelihood of skinerosion by decreasing the friction forces between the device and thescalp. A lubricious material may also minimize fibrous capsule growtharound the device by lowering the friction between the device and thescalp. This would have the additional benefit of reducing the likelihoodof infection.

For many therapies such as brain stimulation for movement disorders itmay be desirable for the device to provide unipolar stimulation wherebythe housing is used as an electrode. Therefore, in some embodiments itmay be desirable to use a lubricious material that is electricallyconductive or to apply the lubricious material to less than the entirehousing.

In one embodiment, housing 82 includes at least a portion of theelectronics for providing monitoring of or therapy to a patient. Someexamples of implantable medical devices that include at least a portionof the electronics for providing monitoring of or therapy to a patientinclude implantable neurostimulators, implantable drug delivery pumps,pacemakers, defibrillators and monitoring devices that receivephysiological signals from a patient and store or relay suchinformation. Such devices that provide therapy to the patient may beopen or closed loop devices (e.g., closed loop device receives sensedinformation and delivers therapy based on the sensed information).

Application of an anti-infection agent and/or lubricious material isalso desirable in the case of a modular device having more than onemodule and housing. In such a case a one embodiment includes ananti-infection agent and/or lubricious material on at least a portion ofboth housings.

An implantable medical device may be implantable anywhere in the body.For example, the implantable medical device may be implanted in theabdomen, pectoral or buttock areas. An implantable medical device mayalso be implanted in the head of a patient such as between the craniumand the scalp. Other embodiments may include an implantable medicaldevice for implantation partially or wholly within a groove or recessplaced in the cranium.

As shown in FIG. 1B, an implantable medical device may be an implantablemedical device 90 for implantation in the head of a patient. Device 90may be placed between the cranium and the scalp. Device 90 includeshousing 92, member 94 and therapy delivery element 96. Member 94provides a substantially smooth interface between device 90 and thescalp or other tissue near the scalp. In one sub-embodiment of thisembodiment, the member 94 partially encapsulates housing 92. Ananti-infection agent and/or lubricious material may be disposed on orimpregnated in the member 94. In one embodiment, the anti-infectionagent and/or lubricious material is provided as a coating 98 on themember 94. In one embodiment the anti-infection agent and/or lubriciousmaterial 98 is only on the convex side of the member 94. Application ofthe lubricious material 98 to the convex side of the member 94 isdesired to reduce friction between the convex side of the member 94 andthe scalp or other tissue near the scalp. However, the lubriciousmaterial may also be applied to more than one side of the member 94.Application of the anti-infection agent may be over all or a part of thedevice. In a cranial application it may be desirable to apply theanti-infection agent to the concave side of the device or member.

In another embodiment the implantable medical device may be a modularimplantable medical device. FIGS. 1C and 1D are conceptual diagramsillustrating a modular implantable medical device 101 implanted within apatient 100. By constructing modular implantable medical device 101 as aset of distributed modules connected together as described herein,modular implantable medical device 101 may be implanted at locations forwhich implantation of conventional implantable medical devices has beendeemed undesirable, thus permitting the implantable medical device 101to be implanted near a monitoring and/or therapy delivery location. Inthe example illustrated within FIGS. 1C-1D, modular implantable medicaldevice 101 is implanted under the scalp of the patient 100 in order tolocate the device 101 close to the location to which therapy is to bedelivered via leads 102, i.e., the brain of patient 100. The low profileand the shape of modular implantable medical device 101 as describedherein can reduce the risk of infection and skin erosion associated withimplantation of matter beneath the scalp, and may provide a cosmeticallyacceptable profile when implanted beneath the scalp.

Modular implantable medical device 101 may deliver stimulation to thebrain of patient 100 to, for example, provide deep brain stimulation(DBS) therapy, or to stimulate the cortex of the brain. Corticalstimulation may involve stimulation of the motor cortex. Modularimplantable medical device 101 may be used to treat any nervous systemdisorder including, but not limited to, epilepsy, pain, psychologicaldisorders including mood and anxiety disorders, movement disorders(MVD), such as, but not limited to, essential tremor, Parkinson'sdisease, and neurodegenerative disorders.

However, modular implantable medical device 101 is not limited todelivery of stimulation to the brain of patient 100, and may be employedwith leads 102 deployed anywhere in the head or neck including, forexample, leads deployed on or near the surface of the cranium, leadsdeployed beneath the cranium such as near or on the dura mater, leadsplaced adjacent cranial or other nerves in the neck or head, or leadsplaced directly on the surface of the brain. Moreover, modularimplantable medical device 101 is not limited to implantation under thescalp of patient 100. Indeed, modular implantable medical device 101 maybe implanted anywhere within patient 100. For example, modularimplantable medical device 101 can be implanted within the neck ofpatient 100, and deliver stimulation to the vagus nerve or the cervicalregion of the spinal cord.

Modular implantable medical device 101 may alternatively be implantedwithin a pectoral region or the abdomen of patient 100 to act as adiaphragmatic pacer, or to provide any of the monitoring and therapydelivery functions known in the art to be associated with cardiacpacemakers. Further, modular implantable medical device 101 may beimplanted in the upper buttock region and deliver spinal cord,urological or gastrological stimulation therapy, or may be configured tobe implanted within the periphery, e.g., limbs, of patient 100 fordelivery of stimulation to the muscles and/or peripheral nervous systemof patient 100. As is the case with cranial implantation, the modularityof implantable medical device 101 may enable implantation at some ofthese example locations for which implantation of conventionalimplantable medical devices is generally deemed undesirable.

Modular implantable medical device 101 is not limited to embodimentsthat deliver stimulation. For example, in some embodiments modularimplantable medical device 101 may additionally or alternatively monitorone or more physiological parameters and/or the activity of patient 100,and may include sensors for these purposes. Where a therapy isdelivered, modular implantable medical device 101 may operate in an openloop mode (also referred to as non-responsive operation), or in a closedloop mode (also referred to as responsive). Modular implantable medicaldevice 101 may also provide warnings based on the monitoring.

As discussed above, the ability of a modular implantable medical device101 according to the invention to be implanted close to a region withinpatient 100 to be monitored enables the use of shorter leads 102.Shorter leads 102 may advantageously improve the accuracy of suchsensors by reducing noise attributable to leads 102. Shorter leads 102may also advantageously reduce the negative affects of imagingtechniques such as magnetic resonance imaging “MRI” on a personimplanted with implantable medical device 101.

Additional alternate embodiments for implantable medical devicesimplemented according to principles of the present invention may alsoinclude non-electrical based therapies such as targeted introduction offluids and similar therapeutic materials using pumps and reservoirs ofmaterial. One skilled in the art will recognize that any number ofimplantable devices may be possible without deviating from the spiritand scope of the present invention as recited within the attachedclaims.

FIG. 2 is a schematic diagram illustrating a modular implantable medicaldevice 201 according to another embodiment of the present invention. Inthis example embodiment, implantable medical device 201 is arranged in atriangular configuration. Modular implantable medical device 201includes three modules: a control module 210, a power source module 211,and a recharge module 212. Each of modules 210-212 includes a respectivehousing. Modular implantable medical device 201 also contains a set oflead connection modules 213 that permits external leads 102 (FIGS. 1Cand 1D) to be connected to control module 210 as needed. In this way,lead connection module 213 is configured to receive external leads 102that are separate from lead connection module 213. The distribution offunctional components of modular implantable medical device 201 intomodules permits modular implantable medical device 201 to possess a thinprofile by spreading the components over a larger surface area.

Control module 210 includes control electronics for controlling themonitoring and/or therapy delivery functions of modular implantablemedical device 201, such as a microprocessor, and may include therapydelivery circuitry. Power source module 211 includes a power source thatprovides energy to control module 210, which in some embodiments is arechargeable power source such as a rechargeable battery and/orcapacitor. Recharge module 212 includes a recharge coil for inductivelyreceiving energy to recharge a rechargeable power source within powersource module 211.

In some embodiments, one or modules may be coupled by coupling modules(not shown). A coupling module may be flexible, and may include a lumento carry a conductor or a fluid between modules of a modular implantablemedical device. In some embodiments, a coupling module is made of aflexible material such as silicone or a flexible polymer. In otherembodiments a coupling module is hermetic and made of substantially lessflexible material, such as titanium or stainless steel, and theflexibility of a coupling module is provided by the configuration and/orconstruction the coupling module.

A coupling module may be flexible in a plurality of directions toprovide modules of a modular implantable medical device with multipledegrees of freedom of motion with respect to each other. In exemplaryembodiments, a coupling module provides at least three degrees ofmotion, and the degrees of motion provided include rotational motion.

Additional details regarding modules 210, 211 and 212, additional oralternative modules for a modular implantable medical device, theinterconnection of modules within a modular implantable medical device,and lead connection modules 213 may be found in commonly assigned U.S.patent application Ser. No. 10/731,869, entitled “MODULAR IMPLANTABLEMEDICAL DEVICE,”; commonly assigned U.S. patent application Ser. No.10/731,699, entitled “COUPLING MODULE OF A MODULAR IMPLANTABLE MEDICALDEVICE,”; and commonly assigned U.S. patent application Ser. No.10/730,878, entitled “LEAD CONNECTIONMODULE OF A MODULAR IMPLANTABLEMEDICAL DEVICE,”.

As illustrated in FIG. 2, modular implantable medical device 201includes a member 214. A member generally serves as a smooth interfacebetween one or more modules and the body tissue.

A member may be made of any material. In one embodiment the member maybe made of a metal. For example, a member may be made of titanium or ofother biocompatible metals. In another embodiment, the member may bemade of a soft, biocompatible material. In other embodiments the membermay be made of multiple materials. An anti-infection agent and/orlubricious material 215 may be on or impregnated in a portion of themember 214 (for example, on the convex side of the member 214).Alternatively, the anti-infection agent and/or lubricious material 215may be on or impregnated in the entire outer surface of the member 214.

Member 214 at least partially encapsulates modules 210-212. Further, aswill be described in greater detail below, lead connection modules 213may be formed in member 214. Member may integrate modules 210-212 into astructure. Member 214 may provide a flexible structure that permits thedevice 501 to conform to a variety of implant locations.

In some embodiments, member 214 may be curved to match the shape of thelocation within a patient in which the device is being implanted. Forexample, implantation of modular implantable medical device 201 underthe scalp of a patient may be accomplished if member 214 is concave (asviewed from the cranium) to substantially conform to the shape of thecranium of the patient and convex (as viewed from the scalp) to providea smooth interface with the scalp or tissue near the scalp and thusreduces the likelihood of skin erosion and other problems associatedwith edges or protrusions pushing against the scalp. Concavity ofmodular implantable medical devices is described in greater detail in acommonly-assigned U.S. patent application Ser. No. 10/731,867, entitled“CONCAVITY OF AN IMPLANTABLE MEDICAL DEVICE”. Any number of shapes maybe used to match a particular implantable medical device 201 to animplantation location for a device.

Member 214 may comprise a solid biocompatible elastomeric material thatis soft and flexible such as silicone. In some embodiments, member 214comprises two or more materials, and two or more components. Forexample, member may comprise one or more elastomeric components formedof an elastomeric material, such as silicone, and one or morenon-elastomeric components formed of a non-elastomeric material, such aspolysulfone, or a polyurethane such as Tecothane®, which is commerciallyavailable from Hermedics Polymer Products, Wilmington, Mass. The one ormore elastomeric components may provide the overall shape andflexibility of modular implantable medical device 201, while thenon-elastomeric components may provide structural integrity for modularimplantable medical device 201, restrict intermodule motion withinmodular implantable medical device 201 to certain ranges, and form apart of the lead interconnection modules 213. Further detail regardingreduction of intermodule motion within modular implantable medicaldevices may be found in a commonly-assigned U.S. patent application Ser.No. 10/731,881, entitled “REDUCING RELATIVE INTERMODULE MOTION IN AMODULAR IMPLANTABLE MEDICAL DEVICE”.

FIGS. 3A-3F are schematic diagrams illustrating various arrangements ofmultiple modules within a modular implantable medical device 301according to various embodiments of the present invention. In each ofthese embodiments, modular implantable medical device 301 has threemodules as discussed above in reference to FIG. 2: a control module 210,a power source module 211, and a recharge module 212. These modules maybe arranged into a variety of configurations, including thoseillustrated, as long as any required interconnections needed between themodules, e.g., coupling modules, may be routed within the device. Thevarious embodiments include triangular configurations, in such as thoseshown in FIGS. 3A-C, and inline configurations, such as those shown inFIGS. 3D-F. The set of lead connection devices 313 may be located invarious locations within the device as well.

In some embodiments, such as those illustrated in FIGS. 3A-C and 3E-F, amember 322 at least partially encapsulates each of modules 210, 211 and212. In other embodiments, such as that illustrated in FIG. 3D, at leastone of the modules of modular IMD 301 is located outside of member 322.Module 212 located outside of member may, as shown in FIG. 3D, betethered to member 322, allowing module 212 to be freely positioned somesignificant distance from member 322. Additional details relating toconfigurations of modules within a modular implantable medical devicesand tethering of modules of an implantable medical device may be foundin a U.S. patent application Ser. No. 10/731,869, entitled “MODULARIMPLANTABLE MEDICAL DEVICE”.

FIGS. 4A-4C are schematic diagrams illustrating a member 422 of amodular implantable medical device 401. FIG. 4A illustrates that themodular implantable medical device 401 comprises a set of modules410-412, and a set of motion reduction elements 421 within member 422,such as motion reduction fibers connecting modules 410 and 411. Modules410 and 411 are also coupled by a coupling module 423.

Because member 422 and coupling module 423 are flexible, member 422 andcoupling module 423 may not provide sufficient motion reduction for themodules 410-412. Specifically, excessive relative motion between modules410 and 411 may compromise the structural integrity of coupling module424, which may lead to failure of modular implantable medical device401. Motion reduction elements 421 are used to provide sufficientstructural integrity to the device 401 once implanted into the patient100 by restricting relative motion between modules 410 and 411 tocertain directions or within certain ranges. Additional detailsregarding motion reduction elements 421 are described in co-pending andcommonly assigned U.S. patent application Ser. No. 10/731,881, entitled“REDUCING RELATIVE INTERMODULE MOTION IN A MODULAR IMPLANTABLE MEDICALDEVICE”.

FIG. 4B illustrates that the member 422 may include two or morecomponents, each component made of a different material. In particular,FIG. 4B illustrates the member 422 includes an elastomeric component 430and a non-elastomeric component 431. The non-elastomeric component 431is typically shaped to surround at least one of modules 410-412, i.e.,is located proximate to sides of at least one of modules 410-412. Insome embodiments, a plurality of individual non-elastomeric components431 surround respective modules 410-412. In other embodiments, anon-elastomeric component 431 surrounds a plurality of modules 410-412to integrate the surrounded modules in a common, semi-rigid structure.

The one or more non-elastomeric components 431 may be used to containone or more modules within elastomeric component 430. Specifically, theone or more non-elastomeric components 431 may be formed to hold modules410-412 within respective positions within elastomeric component 430.Elastomeric component 430 may, as shown in FIG. 4B, at least partiallyencapsulate each of modules 410-412 and provide an desired form factorfor a modular implantable medical device. In some embodiments,non-elastomeric elements 431 are fitted into an elastomeric component430 to form the member 422 before the electronic modules 410-412 areinserted into respective locations within member 422 where they will becontained by non-elastomeric elements 431.

Generally, member 422 provides a number of functions in includingattaching to modules and other elements to provide a smooth interfacesurface for the device as it interacts with the patient, and protectingelectrical connections and feed thru wires needed to connect modules toexternal leads.

Member 422 may be constructed from a durometric specific material toprovide a clinically desirable device. In addition, a material used toconstruct the member 422 may possess a thermal conductivitycharacteristic to either act as a heat sink if needed to dissipate heatfrom modules 410-412, or a material to act as an insulator to shield thepatient 100 from any excess heat from modules 410-412. Because theimplantable medical device 401 may be constructed from a large number ofmodules to perform a desired task, the materials selected for used inconstructing the member 422 may vary as needed by each embodiment.

In embodiments in which member 422 is constructed of components 431 and432, the device 401 may be fabricated by integrating components 431 and432 to form the member 422, constructing the modules 410-412 and theirrespective connection modules 423, and constructing any motion reductionelements 421. Once all of these components are fabricated, the motionrestriction elements 421 may be combined with the member 422, and theinterconnected modules 410-412 may be inserted into the member 422 intorespective positions where they are contained by components 431.

FIG. 4C illustrates that the member 422 provides sloped interface 441between the modules within the device 401 and the patient's bodycomponents. In embodiments in which the device 401 is implanted withintight spaces, such as under the scalp, the sloped interface 441 providesa smooth transition between the body and the device modules 410-412.Protrusions are known to cause possible stress points for tissue that islocated over implanted devices, which can, for example, lead to skinerosion in the case of a device implanted under the scalp. As such, thesloped interface 441 attempts to minimize the transition from themodules 410-412 and the edge of the device 401 to eliminate these pointsof stress. An angle of interface 442 from the patient's body and thesloped interface 441 is greater than 90 degrees. Angle 442 may bebetween 120 and 150 degrees, is preferably between 130 and 140 degrees,and is most preferably approximately 135 degrees.

FIGS. 5A-5B are schematic diagrams illustrating the interaction ofcomponents of an implantable medical device that are part of a member.FIG. 5A provides a side cross-sectional view of a member 522 thatincludes an elastomeric component 530 and a non-elastomeric component531 that interfaces with a control module 610. The non-elastomericcomponent 531 is shaped to mate with and surround the module 510, andmay provide motion reduction for the module. Specifically, thenon-elastomeric component 531 may be mechanically connected to at leastone other module of a modular implantable medical device, e.g., tonon-elastomeric components that surround other modules of an implantablemedical device, by a motion reduction element 521. In other words, themember 522 encapsulates a plurality of modules in this embodiment, andeach of the modules may be surrounded by a non-elastomeric component 531that is connected to other non-elastomeric components by motionreduction elements 521.

A through hole 551 may be located through member 522, e.g., throughelastomeric component 530 and non-elastomeric component 531, to providean attachment point for the implantable medical device. In someembodiments, the implantable medical device may be secured in placeusing bone screws or similar attachment devices that secure the deviceto the patient. Such through holes 551 permit the device to bemechanically attached to the patient once the device is positioned at adesired location.

In addition, elastomeric component 530 is shown as completelyencapsulating the modules and components within FIG. 5. However, in someembodiments, elastomeric component 530, like non-elastomeric component531, may merely surround the module 510 but not cover the top of themodule. Such an arrangement may render the profile of the overall devicesmaller. In such an alternate embodiment, a surface across the memberand the electronics module 510 may minimize transition discontinuitiesto minimize profile changes that may interact with a patient afterimplantation. In other embodiments, one or both components 530 and 531cover a top of module 510, or fully encapsulate module 510.

FIG. 5B illustrates a top view of the member 522 having an elastomericcomponent 530 that covers a non-elastomeric component 531 that surroundsthe control module 510. The through hole 551 used as an attachment pointis shown as part of the non-elastomeric component 531 that is covered bythe elastomeric component 530. The shape of the non-elastomericcomponent 531 and control module 510 are shown as being rectangular inthis embodiment. However, one skilled in the art will recognize that anyshape for the non-elastomeric component 531 and control module 510 maybe used without deviating from the spirit and scope of the presentinvention. Further, the shape of non-elastomeric component 531 need notbe the same as that the shape of the component that it surrounds. Themodules may be restrained within the member 522 using many restraintmechanisms known in the arts including attachment elements, adhesives,snap rings, and similar elements.

While the member 522 described above may be constructed from twodifferent materials, a softer, more flexible elastomeric component 530and one or more harder, more rigid non-elastomeric components 531, oneskilled in the art may recognize that a member 522 may include a singlecomponent made of either class of material to provide the surfacesmoothing, module integration, and structural module restraint featuresdescribed herein.

Finally, the member 522 may include several additional featuresunrelated to the above functions regarding the restraint andinterconnection of multiple modules. In one embodiment, radio-opaquemarkers 561 and 562 may be imbedded within the member 522 to assist indetermining an exact location of an implantable medical device within apatient. These radio-opaque markers 561 and 562 typically possess anon-symmetrical shape to permit registration and orientation of thedevice 501 from imaging of the markers. These radio-opaque markers maybe constructed using barium and similar materials that permit suchimaging. A telemetry and/or recharge coil may be embedded directlywithin the member 522.

It will be understood that an anti-infection agent and/or lubriciousmaterial may be disposed on or impregnated in at least a portion of animplantable medical device. A lubricious material is any material thatwhen applied to an implantable medical device reduces the frictionbetween the implantable medical device and the adjacent tissue. In oneembodiment, the anti-infection agent and/or lubricious material may bedisposed on or impregnated in the housing. For example, ananti-infection agent and/or lubricious material may be disposed on orimpregnated in the housing 90 in FIG. 1A. In another embodiment, theanti-infection agent and/or lubricious material may be disposed on orimpregnated in the member. For example, the anti-infection agent and/orlubricious material may be disposed on or impregnated in the member 94in FIG. 1B. Disposing a lubricious material on or impregnated in amedical device may facilitate insertion of the device into theimplantation location. The lubricious material may also reducepost-implant friction between a portion of the medical device and theadjacent tissue.

It may be desirable to apply the anti-infection agent and/or lubriciousmaterial to less than the entire outer surface of the device. In thecase of an implant between the brain and scalp, the lubricious materialmay be disposed on the side of the device facing the scalp and thereforeprovide for easier insertion of the device under the scalp as well asreduce post implantation friction between the device and the scalp orother tissue. For example, in the case of device 90 when implantedbetween the brain and scalp, the convex side of the member 94 may becoated with a lubricious material 98 to reduce friction between thescalp and the device 90. The anti-infection agent may be applied to theconcave side of the device.

Any known or future developed lubricious material, or combinationsthereof, may be used. Preferably, the lubricious materials are medicallysuitable for inserting into a patient. Examples of suitable lubricousmaterials that may be disposed on at least a portion of a component ofan implantable medical device include fluoroethylpolymer,polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), ethylenetetrafluoroethylene (ETFE), paralene, a hydrophilic polymer, and thelike. Additional examples of suitable coating that may be appliedinclude those described in the following patents and patentpublications: US 20040030159; U.S. Pat. Nos. 6,558,734, 6,278,018;6,603,040; 6,669,994; WO0121326; WO 0144174; and WO 2003055611. In anembodiment, the lubricious material is a hydrogel. The hydrogel may be apolyvinyl pyrrolidone (PVP) hydrogel, such as Medtronic's BIOGLIDE. Inaddition to facilitating insertion of a device, a lubricious materialsuch as a hydrogel may prevent infection, thrombosis and formation of afibrous capsule around the device. For example, BIOGLIDE technology hasbeen shown to resist protein deposition, adherence of thrombosis, andreduce platelet and complement activation and may also inhibit tissueadherence.

Any known or future developed method for applying the anti-infectionagent and/or lubricious material to either the housing or member may beutilized. In one embodiment, the lubricious material may be applied tothe housing or member by being sprayed onto the surface of the housingor member. In another embodiment, the housing or member may be placedinto the anti-infection agent and/or lubricious material allowing theanti-infection agent and/or lubricious material to be retained on orbecome impregnated in the housing or member.

FIG. 15 is a flowchart illustrating one embodiment method of fabricatingan implantable medical device including a lubricious material on thehousing of the module. In this method, the module or modules of thedevice 80 are fabricated at step 1500. At step 1502 a lubriciousmaterial is applied to at least a portion of the housing 82 or multiplehousings of the device 80. It should be understood that the lubriciousmaterial may be applied to the housing either prior to assembly of thecomponents within the housing or after such assembly. Moreover, whenmultiple modules are used, the lubricious material may be applied to thehousings before or after coupling the modules to each other.

FIG. 16 is a flowchart illustrating another embodiment method offabricating an implantable medical device including a lubriciousmaterial on a member. In this method, the member is fabricated at step1600. The fabrication of the member can be by any known or futuredeveloped method. At step 1602, a module is fabricated. At step 1604, alubricious material is applied to the member. The components includingthe member and module are combined at step 1604. As described withregard to the process of FIG. 15, assembly and application of thelubricious material may be performed in any order.

Additional techniques for applying an anti-infection agent areavailable. As discussed above, the anti-infection agent may beimpregnated into the housing or member or it may be applied on thehousing or member as a coating. Alternatively, the anti-infection agentmay be incorporated into (via compounding or other methods) into a thinjacket, pouch, sleeve or thin cover that fits at least partially aroundthe housing. For example, coating layer 86 in FIG. 1A or coating layer98 in FIG. 1B (or any other coating of any of the implantable medicaldevice embodiments) may be an anti-infection coating. Such coatings maybe anti-infection agent, lubricious material or a combination lubriciousmaterial and anti-infection agent.

Any antimicrobial agent, such as an antibacterial agent, an antisepticagent, etc., may be used to prevent infection. Non-limiting examples ofantiseptics include hexachlorophene, cationic bisiguanides (i.e.chlorhexidine, cyclohexidine) iodine and iodophores (i.e.povidone-iodine), para-chloro-meta-xylenol, triclosan, furan medicalpreparations (i.e. nitrofurantoin, nitrofurazone), methenamine,aldehydes (glutaraldehyde, formaldehyde), silver sulfadiazine andalcohols. Nonlimiting examples of classes of antibiotics that may beused include tetracyclines (e.g. minocycline), rifamycins (e.g.rifampin), macrolides (e.g. erythromycin), penicillins (e.g. nafcillin),cephalosporins (e.g. cefazolin), other beta-lactam antibiotics (e.g.imipenem, aztreonam), aminoglycosides (e.g. gentamicin),chloramphenicol, sufonamides (e.g. sulfamethoxazole), glycopeptides(e.g. vancomycin), quinolones (e.g. ciprofloxacin), fusidic acid,trimethoprim, metronidazole, clindamycin, mupirocin, polyenes (e.g.amphotericin B), azoles (e.g. fluconazole) and beta-lactam inhibitors(e.g. sulbactam). Nonlimiting examples of specific antibiotics that maybe used include those listed above, as well as minocycline, rifampin,erythromycin, nafcillin, cefazolin, imipenem, aztreonam, gentamicin,sulfamethoxazole, vancomycin, ciprofloxacin, trimethoprim,metronidazole, clindamycin, teicoplanin, mupirocin, azithromycin,clarithromycin, ofloxacin, lomefloxacin, norfloxacin, nalidixic acid,sparfloxacin, pefloxacin, amifloxacin, enoxacin, fleroxacin,temafloxacin, tosufloxacin, clinafloxacin, sulbactam, clavulanic acid,amphotericin B, fluconazole, itraconazole, ketoconazole, and nystatin.

An antimicrobial agent may be incorporated into or on the housing ormember or a lubricious material using any known or future developedtechnique. For example, the antimicrobial agent may be disposed in or onthe member or underlying coating layer (in one exemplary embodiment theunderlying coating layer may be a lubricious material) throughcompounding or solvent expansion/swelling techniques. A hydrogel, forexample, may be presoaked in a solvent comprising the anti-infectionagent to incorporate the agent. Alternatively, an antimicrobial agentmay be covalently attached to a housing or member or coating materialusing any known or future developed technology. Suitable technologyincludes Surmodic's PHOTOLINK technology. Conventional TDMAC(Tridodecylmethylammonium) coating technology, such as withTDMAC-heparin (Tridodecylmethylammonium heparinate), may also beemployed. Additional technology for incorporating a therapeutic agentinto or on a housing or member that may be used in accordance with theteachings of the present invention are discussed in, for example, U.S.Pat. Nos. 6,303,179, 6,143,354, 5,217,493, US 2004/0039437, and WO04/014448. Of course any other therapeutic agent may be incorporatedinto or on the housing or member or lubricious coating.

As discussed above, another embodiment may utilize coating layers toapply the anti-infection agent to the housing or member. Depending uponthe type of materials used to form coating layers, the coatings can beapplied to the surface of the housing or member or an underlying coatinglayer through any coating processes known or developed in the art. Onemethod includes directly bonding the coating material to a surface ofthe housing or member or underlying coating layer. By directly attachinga polymer coating to the housing or member or underlying coating layer,covalent chemical bonding techniques may be utilized. Housing or memberor underlying coating layer surface may possess chemical functionalgroups on its surface such as carbonyl groups, primary amines, hydroxylgroups, or silane groups which will form strong, chemical bonds withsimilar groups on polymeric coating material utilized. In the absence ofsuch chemical forming functional group, known techniques may be utilizedto activate the material's surface before coupling the biologicalcompound. Surface activation is a process of generating, or producing,reactive chemical functional groups using chemical or physicaltechniques such as, but not limited to, ionization, heating,photochemical activation, oxidizing acids, sintering, and etching withstrong organic solvents. Alternatively, the coating layer may beindirectly bound to the member or housing or underlying coating layerthrough intermolecular attractions such as ionic or Van der Waalsforces.

An anti-infection agent may also be incorporated into a coating layer ina variety of ways. For example, anti-infection agent may be covalentlygrafted to a polymer of the coating layer, either alone or with asurface graft polymer. Alternatively, an anti-infection agent may becoated onto the surface of the polymer or member either alone orintermixed with an overcoating polymer. An anti-infection agent may bephysically blended with a polymer of a coating layer as in a solid-solidsolution. Anti-infection agent may be impregnated into a polymer byswelling the polymer or member in a solution of the appropriate solvent.Any means of incorporating anti-infection agent into or on a coatinglayer may be used, provided that anti-infection agent may be released,leached or diffuse from coating layer, member or housing on contact withbodily fluid or tissue.

A polymer of a coating layer and an anti-infection agent may beintimately mixed either by blending or using a solvent in which they areboth soluble. This mixture can then be formed into the desired shape orcoated onto an underlying structure of the medical device. One exemplarymethod includes adding one or more anti-infection agents to a solvatedpolymer to form a anti-infection agent/polymer solution. Theanti-infection agent/polymer solution can then be applied directly tothe surface of a member (such as member 94 for example) or housing (suchas housing 82), or an underlying coating layer (such as coating layer 98or 86 for example); by either spraying or dip coating the housing ormember. As the solvent dries or evaporates, the anti-infectionagent/polymer coating is deposited on the member or housing.Furthermore, multiple applications can be used to ensure that thecoating is generally uniform and a sufficient amount of anti-infectionagent has been applied.

Alternatively, an overcoating polymer, which may or may not be the samepolymer that forms the primary polymer of the member or underlingcoating layer 25, and anti-infection agent are intimately mixed, eitherby blending or using a solvent in which they are both soluble, andcoated onto member or housing or underling coating layer. Anyovercoating polymer may be used, as long as the polymer is able to bond(either chemically or physically) to the member or housing.

In addition, a polymer of a coating layer may be swelled with anappropriate solvent, allowing a anti-infection agent o impregnate thepolymer.

Anti-infection agent may also be covalently grafted onto a polymer of acoating layer. This can be done with or without a surface graft polymer.Surface grafting can be initiated by corona discharge, UV irradiation,and ionizing radiation. Alternatively, the ceric ion method, previouslydisclosed in U.S. Pat. No. 5,229,172 (Cahalan et al.), may be used toinitiate surface grafting.

FIG. 17 is a flowchart illustrating one embodiment method of fabricatingan implantable medical device including an anti-infection agent on thehousing of the module. In this method, the module or one or more modulesof the device 80 are fabricated at step 1700. At step 1702 ananti-infection agent is applied to at least a portion of the housing 82or multiple housings of the device 80. It should be understood that theanti-infection agent may be applied to the housing either prior toassembly of the components within the housing or after such assembly.Moreover, when multiple modules are used, the anti-infection agent maybe applied to the housings before or after coupling the modules to eachother.

FIG. 18 is a flowchart illustrating another embodiment method offabricating an implantable medical device including an anti-infectionagent on a member. In this method, the member is fabricated at step1800. The fabrication of the member can be by any known or futuredeveloped method. At step 1802, a module is fabricated. At step 1806, ananti-infection agent is applied to the member. The components includingthe member and module are combined at step 1804. As described withregard to the process of FIG. 17, assembly and application of theanti-infection agent may be performed in any order.

FIG. 6 is a schematic diagram illustrating degrees of intermodularmotion that may be present in modular implantable medical device. Forany two modules within a distributed medical device, motion between thetwo modules may include pitch motion 601, yaw motion 602, and rollmotion 603. For the set of motion reduction elements 621 discussedabove, one or more of these three degrees of motion may be limited toprevent mechanical failures of interconnections between the modulesduring use of a modular implantable medical device. Specifically,modules of a modular implantable medical device may be connected byconnector modules, which may be compromised by excessive intermodulemotion. Such interconnect members are described in greater detail incommonly assigned U.S. patent application Ser. No. 10/731,881, entitled“REDUCING RELATIVE INTERMODULE MOTION IN A MODULAR IMPLANTABLE MEDICALDEVICE”.

FIG. 7 is a schematic diagram illustrating motion reduction withinvarious degrees of motion within a modular implantable medical device.For any two modules 701-702 within an implantable medical device, aconnector module 721 may be used between the modules 701-702 to connectelements within these modules 701-702. Motion reduction elements 722 and723 may be used to reduce inter-modular motion, and in some cases, tolimit inter-modular motion to a range of motion.

Motion reduction elements 722 and 723 may be formed as part ofnon-elastomeric components 531 of a member 522 associated with each ofmodules 701 and 702. As shown in FIG. 7, motion reduction elements 722and 723 allow free inter-modular motion within one of the degrees withina range. In some embodiments, one non-elastomeric component includes oneor more motion reduction elements 722. In other embodiments, twonon-elastomeric components 531 include motion reduction elements 722 and723, respectively, which interact to reduce inter-modular motion.

A modular implantable medical device may include any number of motionreduction elements, which may take any of a variety of shapes. In someembodiments, motion reduction elements may be used in all axes tomaximize the amount of motion reduction provided. The implantablemedical device having multiple modules typically requires sufficientmotion reduction to prevent undue mechanical stresses on interconnectionconnection member 721 between the modules 701-702 that may not beprovided by a flexible member 522.

Additional details regarding the set of motion reduction elements 521are described in co-pending and commonly assigned U.S. patentapplication Ser. No. 10/731,881, entitled “REDUCING RELATIVE INTERMODULEMOTION IN A MODULAR IMPLANTABLE MEDICAL DEVICE”.

FIG. 8A is a block diagram illustrating an example embodiment of amodular implantable medical device 801 having a tethered leadinterconnect site 861 according to the present invention. A member 822of implantable medical device 801 at least partially encapsulates andconnects a plurality of modules 810-812 while not encapsulating leadconnection modules 813 that are part of tethered lead interconnect site861. In such embodiments, the implantation of device 801 would notrequire the insertion of external leads into the member 822. Inaddition, the external leads may be located a distance away from thedevice 801. Such an arrangement may assist in the management of theexternal leads as they are placed within the patient and routed to adevice implantation location. Further, location of leads and connectionsite 861 away from member 822 may make it less likely that the leadswill be damaged during a surgical explant procedure.

In alternate embodiments shown in FIGS. 8B-8C, member 822 may possessmechanical structures such as grooves 832, an externally attached pouch833, or an integrated containment cavity 834 to contain and/or route theexternal leads away from the implantable medical device 801 in anefficient manner. In some embodiments, the external leads may possess aminimum length to provide a particular electrical characteristic for theimplantable medical device 801. This minimum length may be greater thana distance needed by a particular patient for some implantationlocations. These mechanical structures that assist in external leadmanagement may accommodate any extra lead material that needs to be partof the device 801 in some implantation embodiments. Because the membermay be spread over an area surrounding the modular device, the membermay cover holes in the cranium formed to allow external leads to accessthe brain. Additional structures, including one or more cap structures835 that secure a lead as it passes through the hole in the cranium maybe an integral part of the member connector module 822.

Additional details regarding the lead connection modules are describedin co-pending and commonly assigned U.S. patent application Ser. No.10/730,878, entitled “LEAD CONNECTION MODULE OF A MODULAR IMPLANTABLEMEDICAL DEVICE”.

FIG. 9 is a block diagram illustrating an example embodiment of amodular implantable medical device 901 having an access loop 971 forremoval according to the present invention. Access loop 971 may bemechanically coupled to, or formed as a part of member connector module922. This access loop 971 may be used to assist in the removal of theimplantable medical device 901 at a point in time when the device 901 isno longer needed by the patient, or at a point in time when a particulardevice 901 needs to be replaced. The device 901 may be encapsulatedwithin the patient 100 with scar tissue fibers such that physical effortwill be required to remove the device 901 from its implantationlocation. This access loop 971 provides a clinician a removal assiststructure to physically manipulate the implantable medical device 901during its removal. This access loop 971 may also be useful duringimplantation of the device 901 as well as it provides a handle tomanipulate the device 901 without handing the member 922 and its relatedmodules. One skilled in the art will recognize that alternateembodiments for the access loop that may include removal handles, astrip cord and a reinforced opening within the member connector moduleto provide a mechanism to grasp the device to assist in removal.

FIG. 10 is a schematic diagram illustrating an example embodiment of amodular implantable medical device 1001 having a triangular modulearrangement according to the present invention. In this embodiment, atriangular arrangement of modules is shown with a member 1022 that atleast partially encapsulates all of the modules. Lead interconnectionmodules 1013 are located between the modules at a common location.Member 1022 provides a slope interface 1041.

FIG. 11 is a schematic diagram illustrating an example embodiment of amodular implantable medical device 1101 having an inline modulearrangement according to the present invention. In this embodiment, aninline arrangement of modules is shown with a member 1122 that at leastpartially encapsulates all of the modules. A lead interconnection module1113 is located on one side of the member 1122. Member 1122 provides aslope interface 1141.

FIG. 12 is a schematic diagram illustrating side view of a multi-moduleimplantable medical device having an inline module arrangement accordingto the present invention. The side view of the device 1201 shows anunderside of the device 1202 that possess a curved shape to permitimplantation at a location having a curved body structure.

FIG. 13 is a schematic diagram illustrating an exploded view of amodular implantable medical device 1301 having a triangular modulearrangement according to the present invention. In this embodiment, yetanother triangular arrangement of modules is shown with a member 1322 atleast partially encapsulating all of the modules. A slope interfaceelement 1341 is shown surrounding the member 1322. In this embodiment,the slope interface element 1341 is shown as a separate physicalstructure, such as a flexible band, an o-ring, removable flexibleflange, or a tapered outer contour element that surrounds the member1322, rather than a tapered portion of member 1322. Slope interfaceelement 1341 provides a desired sloped interface between the edge of theimplantable medical device and the patient. In some embodiments, theshape and contour of slope interface element 1341 may be modified at thetime of implantation to obtain a desired shape, or slope interfaceelements 1341 may be selected at the time of implantation from a varietyof slope interface elements to provide a desired slope interface for aparticular patient.

FIG. 14 is a flowchart illustrating a method of constructing animplantable medical device with a member according to the presentinvention. An implantable medical device 401 may be fabricated byconstructing the member 422 (1401) from a first and second component. Asdiscussed above, member 422 may comprise two or more materials, and twoor more components. For example, member may comprise one or moreelastomeric components formed of an elastomeric material, such assilicone, and one or more non-elastomeric components formed of anon-elastomeric material. Once the member 422 is completed, the modules410-412 with their respective connector modules 423 are constructed(1402). Next, any motion reduction elements 421 included in the device401 are constructed. Once all of these components are fabricated, themotion restriction elements 421 may be combined with the member 422(1403) and the interconnected modules 410-412 may be inserted (1404)into the member 422. From the combination of these components, thedevice 401 is formed.

It should be noted that the anti-infection agent and/or lubriciousmaterial may be on or impregnated in any of the embodiments ofimplantable medical devices provided even though such is notspecifically called out in every Figure and accompanying description.

The foregoing description of the exemplary embodiments of the inventionhas been presented for the purposes of illustration and description.They are not intended to be exhaustive or to limit the invention to theprecise forms disclosed. Many modifications and variations are possiblein light of the above teaching. It is intended that the scope of theinvention be limited not with this detailed description, but rather bythe claims appended hereto.

FIGS. 19A-19B are schematic diagrams illustrating an exemplaryinteraction of components of an IMD 1901. FIG. 19A provides a side viewof an member 1922, which includes one or more soft or elastomericcomponents 1932 and one or more hard or non-elastomeric components 1931,which interface with a control module 1910. Non-elastomeric component1931 may be shaped to mate with the module 1910 to provide motionrestriction for the module. Non-elastomeric component 1931 may bemechanically connected to other modules using a motion restrictiondevice (not shown). The member 1922 covers all of these components inthis embodiment. A through hole 1951 may be located through thenon-elastomeric component 1931 and elastomeric component 1932 to providean attachment point for IMD 1901. In some embodiments, IMD 1901 may beanchored in place using bone screws or other anchoring devices. Throughholes 1951 permit IMD 1901 to be mechanically anchored to the patientonce the device 1901 is positioned at a desired location. In theembodiment shown in FIG. 19A, a bone screw inserted into through hole1951 would seat against non-elastomeric component 1931, but theinvention encompasses embodiments in which a bone screw would seatagainst another component, such as control module 1910.

FIG. 19B illustrates a top view of the device 1901 having elastomericcomponent 1932 of member 1922 covering the non-elastomeric components1931 that frame control module 1910. The through hole 1951 used as anattachment point is shown as part of non-elastomeric component 1931 thatis covered by elastomeric component 1932. The shape of non-elastomericcomponent 1931 and control module 1910 are shown as being rectangular inthis embodiment. However, one skilled in the art will recognize that anyshape for the non-elastomeric component 1931 and control module 1910 maybe used without deviating from the spirit and scope of the presentinvention.

In both FIG. 19A and 19B, a lead interconnect device 1952 is includedwithin the non-elastomeric components 1931 of member 1922. In theseexamples, the non-elastomeric component 1931 restrains control module1910 and external leads 1954, which are separate from lead interconnectdevice 1952. Typically, the external leads 1952 have iso-diametricproximal ends for connection of the external leads 1954 to IMD 1901. Anexternal lead 1954 is inserted into the lead connection module in orderto connect the external leads 1954 to electronics within control module1910 of IMD 1901. This electrical connection from the control module1910 to the external leads 1954 is made using a module connection leadwire 1956 that extends from control module 1910 and physically connectswith the external lead 1954 within the lead connection module 1952.

The lead connection module 1952 may also include a mechanical leadsecuring mechanism 1958 that engages the external lead 1954 to restrainits motion and ensure electrical connection with feed-through wires1956. In the embodiment of FIG. 19A, a tool 1960 is used to engage themechanical lead securing mechanism 1958 within the lead connectionmodule 1952. In this embodiment, the mechanical lead securing mechanism1958 comprises a mechanical set-screw that is tightened by ascrewdriver. An example of such a mechanical lead securing mechanism1958 is a low-profile DBS lead extensions manufactured by Medtronic Inc.In alternate embodiments, the mechanical lead securing mechanism 1958may be tool-less using a variety of known securing technologies thatensures the external lead 1954 does not separate from the leadconnection module 1952. Tool-assisted or tool-less coupling of leads tothe IMD both allow medical personnel to couple leads to the IMD quicklyand securely.

1. An implantable medical device for implantation within the head of ahuman body, the implantable medical device comprising: a first modulecomprising a first housing, wherein the first housing contains at leasta portion of electronics for providing monitoring of or therapy to abrain of a patient; a lead connection module configured to accept anexternal lead and electrically couple the external lead to theelectronics, wherein the external lead is separable from the leadconnection module; an anti-infection agent coated on or impregnated inat least a first portion of the first housing; and a lubricious materialcoated on or impregnated in at least a second portion of the firsthousing, wherein the first and second portions are different.
 2. Theimplantable medical device of claim 1, wherein the implantable medicaldevice is configured for implantation between a scalp and a cranium ofthe human body.
 3. The implantable medical device of claim 2, wherein aside of the first housing facing the cranium of the human body issubstantially concave as viewed from the cranium and the anti-infectionagent is on or impregnated in the substantially concave side of thefirst housing.
 4. The implantable medical device of claim 1 furthercomprising a second module, the second module comprising a secondhousing, wherein the first and second modules are connected, and whereinthe anti-infection agent is coated on or impregnated in the secondhousing.
 5. The implantable medical device of claim 1, wherein theanti-infection agent is absent from at least one side of the firsthousing.
 6. The implantable medical device of claim 5, wherein theanti-infection agent is only coated on or impregnated in one side of thefirst housing.
 7. The implantable medical device of claim 1, wherein thefirst housing is metal.
 8. The implantable medical device of claim 7,wherein the first housing is titanium.
 9. The implantable medical deviceof claim 1, wherein the first housing is ceramic.
 10. The implantablemedical device of claim 1, wherein the anti-infection agent is anantimicrobial agent.
 11. The implantable medical device of claim 10,wherein the antimicrobial agent is one of an antibiotic and anantiseptic.
 12. The implantable medical device of claim 10, wherein theantimicrobial agent comprises the combination of rifampin andminocycline.
 13. The implantable medical device of claim 1, wherein thelubricious material comprises a polymer layer and wherein theanti-infection agent is impregnated in the polymer layer and the polymerlayer is attached to the at least the second portion of the firsthousing.
 14. The implantable medical device of claim 1, wherein the leadconnection module includes a mechanical lead securing mechanism.
 15. Theimplantable medical device of claim 14, wherein the mechanical leadsecuring mechanism comprises a tool-less mechanical lead securingmechanism.
 16. The implantable medical device of claim 1, wherein thelubricious material is electrically conductive.
 17. An implantablemedical device for implantation within a human body, the implantablemedical device comprising: a first module comprising a first housing,wherein the first housing contains at least a portion of electronics forproviding monitoring of or therapy to a patient; a member at leastpartially encapsulating the first module, wherein the member provides asmooth interface between at least a portion of the first housing and atissue of the human body; an anti-infection agent coated on orimpregnated in a first portion of the member; and a lubricious materialcoated on or impregnated in at least a second portion of the member,wherein the first and second portions are different.
 18. The implantablemedical device of claim 17, wherein the anti-infection agent is onlycoated on or impregnated in one side of the member.
 19. The implantablemedical device of claim 17, wherein the implantable medical device isconfigured for implantation in the head of the human body.
 20. Theimplantable medical device of claim 19, wherein the implantable medicaldevice is configured for implantation between the scalp and the cranium.21. The implantable medical device of claim 20, wherein a first side ofthe member facing the scalp is substantially convex as viewed from thescalp.
 22. The implantable medical device of claim 21, wherein theanti-infection agent is only coated on or impregnated in a substantiallyconcave side of the member that is substantially opposite the firstside.
 23. The implantable medical device of claim 21, wherein thelubricious material is only disposed on the first side of the member.24. The implantable medical device of claim 17, wherein the member isflexible.
 25. The implantable medical device of claim 17, wherein themember comprises an elastomeric material.
 26. The implantable medicaldevice of claim 25, wherein the elastomeric material is silicone. 27.The implantable medical device of claim 17, wherein the member comprisesa non-elastomeric material.
 28. The implantable medical device of claim27, wherein the non-elastomeric material is one of a polysulfone and apolyurethane.
 29. The implantable medical device of claim 17, furthercomprising a lead connection module within the member for connecting anexternal lead to electronics within the first module, wherein theexternal lead is separable from the lead connection module.
 30. Theimplantable medical device of claim 17, wherein an edge of the memberprovides a sloped interface with a surface of a patient, and an anglebetween the edge and the surface of the patient is greater than 90degrees.
 31. The implantable medical device of claim 30, wherein theangle is within a range from 120 and 150 degrees.
 32. The implantablemedical device of claim 31, wherein the angle is approximately equal to135 degrees.
 33. The implantable medical device of claim 17, wherein themember comprises a material having a high thermal conductivity to act asa heat sink for thermal energy generated within the first module. 34.The implantable medical device of claim 17, wherein the member comprisesa material having a low thermal conductivity to act as a shield ofthermal energy generated within the first module.
 35. The implantablemedical device of claim 17, wherein the member includes a groove to holdexternal lead material.
 36. The implantable medical device of claim 17,wherein the member includes a pouch to hold external lead material. 37.The implantable medical device of claim 17, wherein the member includesa through-hole to receive an attachment mechanism for attaching theimplantable medical device to a patient.
 38. The implantable medicaldevice of claim 17, further comprising a second module coupled to themember, the second module comprising a second housing, wherein themember provides a smooth interface between the first and second housingsand a tissue of the human body.
 39. The implantable medical device ofclaim 38, wherein the anti-infection material is only coated on orimpregnated in one side of the member.
 40. The implantable medicaldevice of claim 38, wherein the implantable medical device is configuredfor implantation in the head of the human body.
 41. The implantablemedical device of claim 40, wherein the implantable medical device isconfigured for implantation between the scalp and the cranium.
 42. Theimplantable medical device of claim 41, wherein the side of the memberfacing the scalp is substantially convex as viewed from the scalp. 43.The implantable medical device of claim 42, wherein the anti-infectionagent is only coated on or impregnated in the substantially convex sideof the member.
 44. The implantable medical device of claim 38, whereinthe member is flexible.
 45. The implantable medical device of claim 38,wherein the member comprises an elastomeric material.
 46. Theimplantable medical device of claim 45, wherein the elastomeric materialis silicone.
 47. The implantable medical device of claim 38, wherein themember comprises a non-elastomeric material.
 48. The implantable medicaldevice of claim 47, wherein the non-elastomeric material is one of apolysulfone and a polyurethane.
 49. The implantable medical device ofclaim 38, further comprising a lead connection module within the memberfor connecting an external lead to electronics within the first module,wherein the external lead is separable from the lead connection module.50. The implantable medical device of claim 38, wherein an edge of themember provides a sloped interface with a surface of a patient, and anangle between the edge and the surface of the patient is greater than 90degrees.
 51. The implantable medical device of claim 50, wherein theangle is within a range from 120 and 150 degrees.
 52. The implantablemedical device of claim 51, wherein the angle is approximately equal to135 degrees.
 53. The implantable medical device of claim 17, wherein theanti-infection agent is an antimicrobial agent.
 54. The implantablemedical device of claim 53, wherein the antimicrobial agent is one of anantibiotic and an antiseptic.
 55. The implantable medical device ofclaim 53, wherein the antimicrobial agent comprises the combination ofrifampin and minocycline.
 56. The implantable medical device of claim17, wherein the anti-infection agent is impregnated in a polymer layerand the polymer layer is attached to the first portion of the member.57. The implantable medical device of claim 17, wherein theanti-infection agent and the lubricious material are impregnated in themember.
 58. An implantable medical device for implantation within ahuman body, the implantable medical device comprising: a first modulecomprising a first housing, wherein the first housing contains at leasta portion of electronics for providing monitoring of or therapy to apatient; a lead connection module configured to accept an external leadand electrically couple the external lead to the electronics, whereinthe external lead is separable from the lead connection module;anti-infection means coated on or impregnated in at least a firstportion of the first housing for reducing the likelihood of infection tothe body; and lubricious means coated on or impregnated in at least asecond portion of the first housing, wherein the first and secondportions are different.
 59. The implantable medical device of claim 58,wherein the lubricious means is electrically conductive.
 60. Animplantable medical device for implantation within a human body, theimplantable medical device comprising: a first module comprising a firsthousing, wherein the first housing contains at least a portion ofelectronics for providing monitoring of or therapy to a patient; a leadconnection module configured to accept an external lead and electricallycouple the external lead to the electronics, wherein the external leadis separable from the lead connection module; a member at leastpartially encapsulating the first module and the lead connection module,wherein the member provides a smooth interface between at least aportion of the first housing and a tissue of the human body;anti-infection means coated on or impregnated in at least a firstportion of the member for reducing the likelihood of infection to thebody; and lubricious means coated on or impregnated in at least a secondportion of the member, wherein the first and second portions aredifferent.
 61. An implantable medical device for implantation within thehead of a human body, the implantable medical device comprising: aplurality of modules, the plurality of modules comprising a plurality ofhousings, wherein the plurality of housings contains at least a portionof electronics for providing monitoring of or therapy to a patient, andwherein the plurality of housings comprises a lead connection moduleconfigured to accept an external lead and electrically couple theexternal lead to the electronics, wherein the external lead is separablefrom the lead connection module; means for integrating the modules intoa single structure that at least partially encapsulates each of thehousings, whereby the means for integrating the modules provides asmooth interface between the plurality of housings and a tissue of thehuman body; anti-infection means coated on or impregnated in at least afirst portion of the means for integrating for reducing the likelihoodof infection to the body; and lubricious means coated on or impregnatedin at least a second portion of the means for integrating for reducingthe likelihood of infection to the body, wherein the first and secondportions are different.
 62. The implantable medical device of claim 61,wherein the means for integrating is flexible.
 63. The implantablemedical device of claim 61, wherein the means for integrating provides asloped interface with a surface of a patient.
 64. A method forfabricating an implantable medical device configured for implantation ina head of a human body, the method comprising: fabricating a firstmodule, the first module comprising a first housing wherein the firsthousing contains at least a portion of the electronics for providingmonitoring of or therapy to the brain; fabricating a lead connectionmodule, wherein the lead connection module is configured to accept anexternal lead that is separable from the lead connection module andelectrically couple the external lead to the electronics; applying ananti-infection agent to at least a first portion of the first housingfor reducing the likelihood of infection to the body; and applying alubricious material to at least a second portion of the first housing,wherein the first and second portions are different.
 65. The methodaccording to claim 64, wherein the anti-infection agent comprises anantimicrobial agent.
 66. The implantable medical device of claim 65,wherein the antimicrobial agent is one of an antibiotic and anantiseptic.
 67. The method according to claim 65, wherein theantimicrobial agent comprises the combination of rifampin andminocycline.
 68. The method according to claim 64, wherein the step ofapplying an anti-infection agent to the first housing comprises sprayingan anti-infection agent onto the first housing.
 69. The method accordingto claim 64, wherein the step of applying an anti-infection agent to thefirst housing comprises placing the first housing into theanti-infection agent.
 70. The method according to claim 64 furthercomprising fabricating a second module comprising a second housing,connecting the first and second modules, and applying an anti-infectionagent to the second housing.
 71. The method according to claim 64,wherein the implantable medical device is configured for implantationbetween a scalp and a cranium of the patient.
 72. The method accordingto claim 64, wherein the step of applying an anti-infection agentcomprises incorporating the anti-infection agent into a polymer layerand attaching the polymer layer to the first housing.
 73. The methodaccording to claim 72, wherein the polymer layer comprises thelubricious material.
 74. The method of claim 64, wherein the lubriciousmaterial is electrically conductive.
 75. A method for fabricating animplantable medical device, the method comprising: fabricating a memberconfigured to provide a smooth interface between the implantable medicaldevice and a tissue of a human body; fabricating a first module; atleast partially encapsulating the first module with the member toconstruct the implantable medical device; applying a lubricious coatingto a first portion of the member; and applying an anti-infection agentto a second portion of the member for reducing the likelihood ofinfection to the body, wherein the first and second portions aredifferent.
 76. The method of claim 75, wherein the anti-infection agentis an antimicrobial agent.
 77. The implantable medical device of claim76, wherein the antimicrobial agent is one of an antibiotic and anantiseptic.
 78. The method according to claim 75, wherein the membercomprises a solid biocompatible elastomeric material that is flexible.79. The method according to claim 75, wherein the step of applying ananti-infection agent to the member comprises spraying an anti-infectionagent onto the member.
 80. The method according to claim 75, wherein thestep of applying an anti-infection agent to the member comprises placingthe member into the anti-infection agent.
 81. The method according toclaim 75, wherein the implantable medical device is configured forimplantation within a head of a patient.
 82. The method according toclaim 75, wherein the implantable medical device is configured forimplantation between a scalp and a cranium of the patient.
 83. Themethod according to claim 75, wherein the step of applying ananti-infection agent comprises incorporating the anti-infection agentinto a polymer layer and attaching the polymer layer to the member. 84.The method according to claim 83, wherein the polymer layer comprises alubricious material.
 85. The method according to claim 75, wherein thestep of applying the anti-infection agent comprises compounding theanti-infection agent with the member.